[PATCH] Fix AMCC 44x SPD SDRAM init code to support 2 DIMM's

This patch fixes a problem that occurs when 2 DIMM's are
used. This problem was first spotted and fixed by Gerald Jackson
<gerald.jackson@reaonixsecurity.com> but this patch fixes the
problem in a little more clever way.

This patch also adds the nice functionality to dynamically
create the TLB entries for the SDRAM (tlb.c). So we should
never run into such problems with wrong (too short) TLB
initialization again on these platforms.

As this feature is new to the "old" 44x SPD DDR driver, it
has to be enabled via the CONFIG_PROG_SDRAM_TLB define.

Signed-off-by: Stefan Roese <sr@denx.de>

1 files changed, 27 insertions, 4 deletions

diff --git a/cpu/ppc4xx/44x_spd_ddr.c b/cpu/ppc4xx/44x_spd_ddr.c
index 32d44dbe56..10b4c18978 100644
--- a/cpu/ppc4xx/44x_spd_ddr.c
+++ b/cpu/ppc4xx/44x_spd_ddr.c
@@ -46,6 +46,7 @@
 #include <asm/processor.h>
 #include <i2c.h>
 #include <ppc4xx.h>
+#include <asm/mmu.h>
 
 #if defined(CONFIG_SPD_EEPROM) &&					\
 	(defined(CONFIG_440GP) || defined(CONFIG_440GX) ||		\
@@ -229,6 +230,22 @@
 #define TRUE			1
 #define FALSE			0
 
+/*
+ * This DDR2 setup code can dynamically setup the TLB entries for the DDR2 memory
+ * region. Right now the cache should still be disabled in U-Boot because of the
+ * EMAC driver, that need it's buffer descriptor to be located in non cached
+ * memory.
+ *
+ * If at some time this restriction doesn't apply anymore, just define
+ * CFG_ENABLE_SDRAM_CACHE in the board config file and this code should setup
+ * everything correctly.
+ */
+#ifdef CFG_ENABLE_SDRAM_CACHE
+#define MY_TLB_WORD2_I_ENABLE	0			/* enable caching on SDRAM */
+#else
+#define MY_TLB_WORD2_I_ENABLE	TLB_WORD2_I_ENABLE	/* disable caching on SDRAM */
+#endif
+
 const unsigned long test[NUMMEMTESTS][NUMMEMWORDS] = {
 	{0x00000000, 0x00000000, 0xFFFFFFFF, 0xFFFFFFFF, 0x00000000, 0x00000000,
 	 0xFFFFFFFF, 0xFFFFFFFF},
@@ -259,6 +276,7 @@ typedef struct bank_param BANKPARMS;
 #ifdef CFG_SIMULATE_SPD_EEPROM
 extern unsigned char cfg_simulate_spd_eeprom[128];
 #endif
+void program_tlb(u32 start, u32 size, u32 tlb_word2_i_value);
 
 unsigned char spd_read(uchar chip, uint addr);
 
@@ -377,6 +395,11 @@ long int spd_sdram(void) {
 	total_size = program_bxcr(dimm_populated, iic0_dimm_addr,
 				  num_dimm_banks);
 
+#ifdef CONFIG_PROG_SDRAM_TLB /* this define should eventually be removed */
+	/* and program tlb entries for this size (dynamic) */
+	program_tlb(0, total_size, MY_TLB_WORD2_I_ENABLE);
+#endif
+
 	/*
 	 * program SDRAM Clock Timing Register (SDRAM0_CLKTR)
 	 */
@@ -1330,11 +1353,11 @@ unsigned long program_bxcr(unsigned long* dimm_populated,
 			 */
 			cr |= SDRAM_BXCR_SDBE;
 
-			for (i = 0; i < num_banks; i++) {
-				bank_parms[ctrl_bank_num[dimm_num]+i].bank_size_bytes =
+ 			for (i = 0; i < num_banks; i++) {
+				bank_parms[ctrl_bank_num[dimm_num]+i+dimm_num].bank_size_bytes =
 					(4 * 1024 * 1024) * bank_size_id;
-				bank_parms[ctrl_bank_num[dimm_num]+i].cr = cr;
-			}
+				bank_parms[ctrl_bank_num[dimm_num]+i+dimm_num].cr = cr;
+ 			}
 		}
 	}